Am I being dumb, or.....(good turbo question inside!)

OK, now I have never claimed to be a diesel turbo expert for one simple reason, because I haven't quite figured out what the dynamics are with our quite high pressure ratios and how it effects flow in and out of the engine.

However with gasoline turbochargers I feel much more competent in regards to dynamics of flow. In basic, with lower pressure ratios, flow has a large determining factor on power output for these gasoline engines. Especially on the exhaust side, the effects can mean 20-50hp for properly designed exhaust plumbing.

Now here is the question on my mind, "Why are there not more more intricate designs for exhaust and why do we not utilize external wastegates?"

I can understand why for the towing folk and pullers because they need the reliability, but what about the racers? Why aren't there nice tubular stainless steel manifolds available with custom large external wastegates being used? I would ASSume that the increased flow out of the exhaust and more efficient use of the wastegate would result in lower TOTAL boost in the system while creating the same if not more horsepower due to the obvious reasons of a cooler more efficient use of the air charge.

Am I wrong in this assumption? are the gains not there to make it worthwhile? Maybe the head on a 12/24 Valve engine flows like a stuck pig and it doesn't matter about flow, I don't know. I've been pondering this for a long time and I just can't find any answers.

ps: I'm not talking about "Drive pressure:boost pressure", I'm talking about total boost pressure being much higher than a gasser

thanks, I hope someone can shed some light over here so I can stop :bang

thanks
Ken

Much of the "no external" wastegate crowd is due to the complications in plumbing. People are scared of running something taht doesn't just 'bolt on'. I ran into more fab work to get my former Precision turbo & external gate to bolt up than just bolting on an internal 66. Plus, with people running compounds, it's much easier to plumb with internal gates.

JMHO, FWIW, YMMV...
brnadon.

^Ditto ease of assemby makes a big difference- so does room to work with.

OK, so it could be worthwhile, just no one wants to waste their time with it. Gotcha :thankyou2:

R u Ken Diaz hehe anyways I guess you want to c a front mounted turbo like the rest on the Racers in the drag world has went with , and a step header

Whos the guy with the twin set-up that dosen't use any wastegate at all, I think he uses large exhast housing.

And a stuck pig breathes way better than a 12v head.
<<< have a TiAL F38 on my 96

The custom tubular header has been tried, but I don't think the results that were found along with the durabilities vs a cast exhaust manifold make it worthwhile an effort..... I wouldn't mind being proved wrong thoughLOL

Rods said:

R u Ken Diaz hehe anyways I guess you want to c a front mounted turbo like the rest on the Racers in the drag world has went with , and a step header

Click to expand...

No, not diaz, I was thinking of adding a wastegate to my truck because right now it is non-wastegated and the EGT's are through the roof.

I was thinking that a wastegate could lower drive pressure and EGTs and I was wondering if it would be worthwhile to add an external gate for about $300, or just have TAD fab up the integral gate for $250

I push about 47lbs but I have no idea on what my drive pressure is. maybe I'll get a gauge this weekend

I would recommend the internal gate unless you want to fab the external gate yourself. It also depends how long the truck would be down. Not being the best fabricators in the whole world, Lavon and I took about 20 hours of fab for the turbo and external gate that Wayne's (Jff24Gordn) running.

brandon.

Fabrication can be a royal pain but the adjustability of having two external gates and regulaters is awesome, 40psi-100psi at your finger tips.

Riles any pics of your twin set-up? Where is J&H?

I'm not computer literate enough yet to post pictures, but I am working on it. J and H is in Redding CA. (530) 245-0176

If you are planning on using external gates, the gasket for a 2 bolt flange that looks like a header gasket is crap. You need the firering gasket. The pic is a cheep one that brandon said had like 500 miles on it, and the pretty one is a firering one with 5000 miles and all at or above 800*.
The rest of the pics is the single setup brandon is talking about.
And it looks to me that it wouldnt be too hard to put a F38 sitting sideways comming off of the adapter plate between the hotpipe and the AC lines.

Cool, thanks.....where did you source the spacer?

Here's pics of my GT4088R, Tial F38 install...I started building the spacer Friday night from 6-9PM, me and a buddy worked from Noon-10PM Saturday, and Noon-6PM Sunday to get everything done. It was a big job to do, just to go twins in 6 months

GT4088R/Tial F38

Chris

the spacer was the easy part......
http://www.competitiondiesel.com/forums/showthread.php?t=4507

Where are you guy's getting the flanges from? How are you keeping the flanges straight while welding?

prolly sanded down with a belt sander after welding, am i right? at least that's what I would do

Yep. Just a DA and a straight edge after welding. Even the 1/2" flanges warp.

brnadon.